Who is responsible for issues caused by Epic's store? What are the ramifications from an API point of view? Will having another store change the limitiations imposed on what can or can't be done? If so, people already have a choice - Android.
Another reply said "censor" which implies speech, but Apple's rejections can be more fundamental.
Have an app you want to ship? Apple gets to decide whether you meet "minimum functionality requirements". You cannot distribute your app to paying consumers without their approval.
Doing something truly unique, perhaps with some hardware in the phone? Apple may decide they simply do not want this feature in an app on the App Store. Which means you cannot distribute your app to consumers.
I'm less concerned about having other "stores," I just want a way to buy apps from legit developers that don't involve Apple dictating look and feel and entire feature sets.
You know, the same way I can purchase and run software on a Mac without Apple being involved in the transaction.
Apple's rules are completely arbituary, so many apps simply don't exist due to vague guidelines. There are zero 4chan apps on the app store, but a dozen reddit apps (which is ironic given recent news over there). There are dozens of these odd edge cases based on Apple's whimsy that just means there are zero IOS options for what Android has dozens of, even before getting into "obviously" banned content like adult apps and piracy.
So while a few (like, literally 5-10) blockbuster game companies may take the PC launcher route if this wins, there are several smaller time apps that can benefit form this if the app store wasn't the only source of downloading here.
The option to install applications that are censored by the the Default App Store for whatever reason.
Plus, this case probably has pretty far reaching implications on the future of computing. If Apple is allowed to lock down their phones & tables, can they do so with Mac OSX? If Apple can do so with OSX, can Microsoft do the same and lock down Windows to prevent apps from being installed outside of their App Store?
If Microsoft can lock down Windows like iOS/OSX, can Dell lock down their servers to prevent other operating systems from being installed?
Being able to have Microsoft XCloud (and other cloud gaming) as a native app instead of forced to only have the Apple games/arcade.
This is one example of a completely legitimate scenario in a very popular entertainment category and yet it's blocked because of Apple's arbitrary rules of what you can do on your own device.
It would be a significant barrier to entry for them to completely remove it, and I imagine they would lose many users if they did so.